For example, a liquid crystal display device such as a liquid crystal television requires a separate backlight device as an illumination device since the display panel thereof, which is a liquid crystal panel, does not emit light. Such backlight devices are broadly classified as direct-lit backlight devices and edge-lit backlight devices in accordance with the structures thereof. In order to achieve a further reduction in the thickness of the liquid crystal display device, it is preferable to use an edge-lit backlight device.
In such an edge-lit backlight device, a light guide plate that guides light that has been emitted from light sources such as light-emitting diodes (LEDs) toward a light-exiting surface provided at one surface of the light guide plate is housed inside a casing. Since members such as optical sheets and a liquid crystal panel are arranged on the light-exiting-surface side of the light guide plate, a member is needed to support the edges of these members.
Patent Document 1 discloses a backlight device in which the edges of members such as optical sheets are supported in this way. In this backlight device, the edges of optical sheets and the edges of a liquid crystal panel are supported by a backlight chassis arranged so as to surround the light guide plate. Consequently, in this backlight device, the optical sheets and the liquid crystal panel are supported outside of the light-exiting surface of the light guide plate.